Really curious at what point making factual claims about content on a website and then those factual claims forming the basis for a boycott/ending ad spend beco

Really curious at what point making factual claims about content on a website and then those factual claims forming the basis for a boycott/ending ad spend becomes illegal collusion. If a cartel of companies says "let's drive this ad service out of business" that seems plainly to be a trust enforcement issue. But the issue here is twitter made a bunch of business decisions that made brands feel like continued advertising on the platform would damage their brands. So is a mass exodus of clients following a bunch of moderation decisions that allow repulsive content back on the site a trust enforcement issue? I think plainly not.